closes #204

Coccinelle patch performing most changes included.

Problem was the function is copied from another one which
always decrements the arcount and trims the TSIG RR. But with
aggregated responses, this should be stripped not from first,
but from the packet actually containing the TSIG.

Not much refactoring done, just that the algorithm name must be
known in advance, so a correct RDATA length can be calculated.

libknot/dnssec now contains interface for:
- key loading
- low level DNSSEC signing
- NSEC3 hash computation
- SIG(0)
- generating NSEC/NSEC3 records for zones
- generating RRSIG for zones

All dnames are now duplicated instead of refcounted,
this is excessive for some cases but should be refactored later on.
For example node and all its RRSets have the same owner but each its
own copy.

There are still (marked) several leak points, as the names are not
referenced counted now. But this should be addressed as a part of
node/rrset refactoring efforts.

refs #21

Move (and sometimes add) #include <config.h> at the top of
all *.c files.

Remove all #include ["<]config.h[">] from headers files.

Change-Id: I1df07602d0240affd95e12fccd122558300d2145

Change-Id: I429b3833c5db9e78220beb1ea72980b557ba06c4

refs #2137

Change-Id: Iacb0825ef124ca033105010655947a1282844123

refs #2137

Change-Id: Ic8adef04228925e5c8131431c2a126d31310a488

Change-Id: I0a751268fb674e65ca5ccd141c037a9fab67f096

refs #2353

In old (pre-rrset-change) version, the TSIG error was set only in
case it was BADTIME. I'm not sure whether any other error can get
into this function, but it does not matter, it should behave in
the same way as before.

This is because BADTIME affects wire size and we
need to know it in advance.

- Moved several functions to rrset.h.
- Fixed compilation warnings.
- Makefile.am changes.

- Other modifications - added extra param type for compression info.
- Moved around with existing structures a bit
- Made compress_dname function public.

Conflicts:
	src/libknot/tsig.c

refs #2137 @1h

fixes #2145

Old implementations were second party code uder GPL licence. New implementations
have clearer interface, should be faster and can be published under BSD licence
in the future.

refs #2137 @24h

refs #937

Conflicts:

	src/knot/server/zones.c

refs #2045 @30m

fixes #1772 @2.5h

Conflicts:

	src/knot/server/tcp-handler.c
	src/knot/server/xfr-handler.c
	src/knot/server/zones.c
	src/libknot/nameserver/name-server.c
	src/libknot/updates/xfr-in.c
	src/tests/libknot/libknot/response_tests.c